Electric switch



- July 17, 1928. 1,577,713

H.. D. DUN-19N ELECTRIC SWITCH Filed May 28. 1926 3 sheets-sheet 1 Ju1y'17, 192s, V 1,677,713

H. D. DUNTON ELECTRIC SWITCH 5 Sheets-Sheet 2 Filed May 28, 1926 1 AHis A'bbrney.

H. DQDUNT'ON ELECTRIC SWITCH July 17, 1928.

3. Sheets-Sheet 3 Filed May 28. 19.26

' hm/ erwclorz Harris D. Dunjcorw, by .'Hs Atlcor'hey.

Patented July 1'7, 1928.

UNITED STATES PATENT OFFICE.v

HARRIS D. DUNTON, OF SCHENECTDY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION 0F NEW YORK. I

ELECTRIC SWITCH.

Application led May 28,

My invention relates to improvements in electric switches, such as circuit breakers for interrupting electric circuits on the occurrence ofabnormal circuit conditions, and has for an object to provide an improved circuit breaker which can not be maintained in theV circuit closed position during the existence of predetermined conditions. t

My invention will be better yunderstood 'from the following description taken in connection with the accompanying drawings, and its scope will be pointed ou't in the appended claims.

In the accompanying drawings, Fig. 1 1s a side elevation of a circuit breaker embodying my invention and shown in the circuit closed position, Figs. 2 and 3 are similar to Fig. 1 except that the circuit `breaker is shown in the partly open and fully open positions, respectively, and Fig. 4 illustrates in perspective a part of the circuit breaker mechanism.

Referring now in particular to Figs. 1, 2, and 3, I have shown my invention embodiedin an electric switch which, for the purpose of. illustration, is shown as a single pole carbon break circuit breaker, butI my invention is not limited to a single pole circuit breaker or to a circuit breaker of the type having relatively movable cooperating contacts separable in air. In these igures, the circuit breaker is shown mounted on a suitable supporting structure such as a base or panel 10 of insulating material. The circuit breaker comprises relatively movable cooperating Y. 'contacts including stationary contacts 11 an 12 having studs 13 and a movable contact or electric current conducting member .such as a resilient brush 14 cooperating with the contacts 11 and 12 to control a circuit through the circuit breaker. The circuit breaker may be provided -with cooperating secondary and tertiary contacts 15 and 16 respectively, to -take the arc wheny the circuit breaker' is opened. I Y l For moving the brushl 14 to the circuit y'closed position, the circuit4 breaker4 is provided with a trip-free operating mechanism embodying my invention. In the illustrated type of circuit breaker to which my invention is particularly applicable, this mecha` nism comprises an operating member such as a handle lever 17, mounted on a floatingcenter such as the pivot 18 which is Inova-bly 1926. Serial No. 112,401.

supported as by the free ends of links'19, the other ends of which are mounted on a stationary pivot 20. The movable circuit controlling member 'or brush 14 is suitably secured to a brush carrying member or switch arm 21 which is mounted on a stationary pivot 22 and biased by the strain on the brush and gravity to the circuit open positlon.

In order to tie the switch arm 21 to the operating lever 17 for movement thereby to the circuit closed position so that a rigid connection cannot'be maintained between them when the switch is operated during the existence of abnormal conditions, I provide.` in accordance with my invention, between these members a variable length connection which is subject to change under the bias of the arm"21. The link 23 is slotted and connected through the slot 24 to one of the members of the circuit breaker mechanism. such as the lever 17, by the pivotrl18, and is suitably connected to another member of the mechanism, such as the' arm 21, as by a pivot 25. In order to have a change in the effective length of the Vlink 23, that is, the distance between the pivots 18 and 25, the slot 24 is so formed that the path' ofmovement relatively to the link of the center of the pivot 18 as,the'link moves from one position to another on the pivot 18, has a variable radius of curvature, which is a maximum when the pivot 18 is in the upper end of the slot 24 as in Figs. 1 and 3, and a minimum when the pivot 18 is in the lower end of the slot as in Fig. 2. The slot 24 may be kidney-shaped, as shown, with a'hump or inwardly extending portion 26, the purpose of which will hereinafter be explained. v

With this arrangement, it is obvious that the link 23 is constructed and arranged for both rotatory and translatory movement relatively to the operating lever 17. In order toprevent suchmovement when the link 23 is in a position relatively to the lever 17 such thatthe effective length of the link is la assignee as this invention.

1Q the tail portion 30 of the main latch, and a spring 31 for biasing the latches to the latching position. The springl 3l is so connected to the latches 27 and 29 relatively to the respective pivots 32 and 33 thereoil as to exert on the latches torques substantially directly proportional to their finasses.

For releasing the latching means, and thereby eiecting the opening of the circuit breaker, a trip lever, which, as shown, is

mounted on a pivot 34 in the switch arin 21, has 'an arm 35 which, on movement ot' the trip lever in one direction, clockwise as shown in the drawings, moves the latch 29 out of engagement with the tail portion ..25 of thelatch 27. This latch 27 is so constructed and arrangedas to cause it to slide off the lug 28 of the link 23 when released by the latch 29. This is accomplished by having the angle whose vertex is the latch- 30 ing point and which is determined by the latching point and the pivots 25 and 32 obtuse. The trip lever may be actuated to release the latchl 29, either manually, as by pushing on a knob 36, secured to anarm of the trip lever, or automatically by an electroresponsive device. This device may be operative in response to abnormal conditions on the circuit controlled by the circuit breaker. 'Such a .device is herein illus- 4o l trated as comprising a magnetic frame or =yoke 37 operatively related to one terminal or contactll of the circuit breaker, as is well known to the art, and a cooperating armature 38 which :is arranged when atl tracted to the frame 37 as on the occurrence of excess currents to engage an arm 39 on the trip lever and thereby effect the release ot the latches' 27 and 29. The weight of the trip lever is so distributed as normally to vtend to turn it counter clockwise against a stop 40 on the switch arm 21. The electroresponsive device is provided with means for varying its range of operation. Thismeans, as illustrated, comprises a calibrating screw 41 which su ports the free end of the arma-v ture 38 and 1s adjustable to control the initial position thereof. V

While the ele'ctroresponsive device shown 1s of the ty'peresponsive to predetermined current conditions, it is to be yunderstood J that my invention is notJ limited to this means for actuating'a tripping member arranged to release the latch 29, the means shown being merely .illustrative of one device I may use. Obviously, I may use any means,

either automatic in action and operative in response to some predetermined condition, or manually operated, the only requisite being that the means be adapted to be operated to release the latch 29.

The links 19 and the link 23 ilorm a toggle Vwhich, in the closed position oi" the circuit breaker, as shown-1n Fig. 1, is underset, that 1s, the pivot 25 does not cross the line through .the centers-otl the pivots 18 and 2U when the arm 21 is moved to the circuit able means such as a catch 42. mounted on av pivot 43 in the operating lever and arranged to slide over and engage a. projection such as a pin 44 on the arm 21. The length of the toggle 2l-23 may be considered as the sum of the distances between the center of the pivot 25 and the centers of the pivots 18 and 22 respectively. This toggle length varies in accordance with the eil'ective length ot' the link 23 and is greater than the distance between the pivots 18 and 22 when the pivot 18 is in the upper portion of the slot 24. In the closed position of the circuit breaker, the biasing :torce due to the brush pressure and also to gravity exerts on the link 23 a force which acts through the pivot 25 and tends to rotate the link 23 on the pivot 25, but the rotation is prevented by the latches 27 and 29 while in the latching position.

Vhen the vlatch 29 is released as b v clockwise movement of the trip lever, the link would be free to rotate on the pivot 25 if this pivot werel not constrained to move in lthe arc of a circle whose radius is the vdistance between the pivots 22 and 25. Consequently, the link 23 under the forces acting thereon, tends to rotate about the pivot 25 and thereby to increase the distance between the pivots 18 and 22. Since the pivot 18 can not move relatively to the pivot 22 to increase this distance while the latch 42 engages the pin 44, the link 23 is translated or moved bodily on the pivot 18 to the final position shown in Fig. 2. This movement decreases the distance between the pivots 18 and 25 and consequently the sum of the distances between' the pivot 25 and the pivots' *i 18 and 22 respectively to a value equal to'or less than the distance between the pivots 18 and 22. The toggle center or pivot 25 of the overset toggle 21-23 can therefore cross back over the line-joining the pivots 18 and 22 to the underset position shown in .Fig.'2 where the circuit breaker 'is partly open. In this position, the spring 31 mainlains the latch 29 against the arm 35 of the tripping lever which is against the stop 40, and the latch 27 against al lug on the latch 29.

Inorder to reset the link 23 to its initial position or position of maximum effective length after the collapse of the toggle 21-23, I provide suitable means such as a lug 45 on the link 23 arranged in the path A:of movement of a cooperating lug 46 on the it clockwise from the position shown inv Fig. 2 to the position shown in Fig. 3, and

further stressing the spring 31.

In order to close the circuit breaker, the

link 23 must iirst be latched to the operating lever 17. To do this, the operating lever is moved counter clockwise from the full line position shown in Fig. 3 to the dot and dash line position. Counter clockwise movement of the catch 42 about its pivot 43 is limited by a stop 48 on the operating lever so that the catch 42 rides clear of the pin 44 as the lever is moved to latching position. In this movement of the lever 17, the'latch 27 slides along the edge 47 of the link 23 under the bias ofthe spring 31 until it pa'sses on to thew lug 28. The latch 29, also under the bias of spring 31 and clear of the trip lever arm 35, engages the tail 30 of the latch 27, as shown by the dot and 'dash lines. The link 23 is now in effect" a rigid arm of the operating lever, which, when moved clockwise` oversetshthe toggle 21-23 and moves the switch arm 21 into the circuit closing` position. During the clockwise movement of the lever 17 to close the circuit breaker,

of the various, cooperating parts. In' the closing movement of the lever 17 a lug 49 thereon abuts the arm 21 and prevents any possibility of oversetting the toggle 19-23. When the operator stops pulling or pushing down on the operating lever'17, the bias of the parts takes up all' lost motion so that lthe lug 49 does not-abut the arm 21, as

shown in Fig. 1. Obviously, if any attempt is made to close the circuit breaker while abnormal line conditions prevail, the trip leverwill be actuated 'as soon as the circuit is completed through` the circuit breaker. Consequently. the link 23 will be released position, even though the operator still holds down on thehandle. lever 17 The circuit breaker, therefore, cann'ot be maintained closed during t-he existence of predetermined conditions, such as an abnormal circuit condition, or 1n other words, ls'trlp-free from.

the handle.

While I have 'shown `and described only one embodiment of my invention, I do not desire wto be limited to the exact arrangement shown and described. but seek to cover in the appended claims all those modifications that fall Within the-true spirit and scope of mv invention.,

and the brush 24 will take the circuit open lfVhat I claim as new and desire to secure by Letters Patent of the United States,

ment of the link pivotlrelatively to the' link has a variable radius of curvaturewhereby toperinit a change in the distance between the connections/of the link to the respective members.

, 2. A 'movable switch member, an operatino'l member, a link connectin the members, 'said link being slotted andpivoted through the slot to one of the members, the slot being so shaped that'the path of movementofthe link pivot relatively to the link has a variable radius of curvature whereby toper-v mit a change in the distance between the connections of the link to the respective members, and latching means for holding one of said members and said link against relative movement.

3. A pivoted switch arm, a pivoted operating lever` therefor, and a link pivoted to the arm, p said link being slotted and pivoted through the slot for .movement'on the pivot of the operating lever, the path of movement of the pivot relatively to the link having a variable radius of curvature whereby to permita change in the distance between thei link pivots.

4. A pivoted switch arm, a pivoted operatinoilever therefor, a link pivoted tothe arm,y

said link being slotted and pivoted throu h the slot for movement on the pivot of t e operating lever, the vpath. of movement of the pivot relatively to the link having a variable radius of curvature, whereby to permit a change in the' distance between the linky pivots, and latchii'ig means arranged latching means Jr'or preventing such movement whereby under the bias of the arm when in the other position a change in the length of the toggle. is produced to allow the movement of the larm to the one position upon the release of the latchingv means.

6. A pivoted circuit controlling member biased for movement to the circuit open position, an operating lever ior moving the member to thecircuit closed position, a link connecting the member and the lever, said link being constructed and arranged for rotatory and translatory'movement on the pivot of the lever and being subjected to the bias of the member, latching means arranged on movement of the lever in one direction to engage the link in one position and to hold it and the lever against relative movement, said link and member forming a toggle whose length in the latched position of the link is greater than the distance between the pivots ot the member and the/lever whereby on movement of the operating member in the `opposite direction the member' is moved to the circuit closed position.

7. A pivoted switch member biased for movement to one position, a pivoted operating member for moving the switch member to another position. a variable length connection between said members comprising a, slotted link pivoted through the slot to one of the members, the slot being constructed and arranged to provide a path .of movement for the link pivot relatigely to the link having a variable radius of curvatnrefwhereby to change. the length of the-connection and Alatching means for holding the link in a position to 4maintain the maximum length of the connection against the bias of theswitch`member, said link and said switch member vforming a toggle arranged to -be overset on movement of the operating member in a direction to move the switch mem- 1 ber to the other position.

8. A pivoted switch member biased for movement to one position, a pivoted operat- .ing member for moving the switch member to another position, a variable length confor the link pivot relatively to the link having a variable radius of curvature whereby to change the length of the connection, latching means for holding the link in a position to ymaintain the maximum length of the connection against thebias of ,the `4switch member, said link and said switchl member forming a toggle arranged to be overset and restrained on movement of the operating member in a direction to move the switch member to the other position, and means for releasing the' latchinfe,` means whereby under the bias of theswitch member the link is moved to a position-to shorten the length ot' the connection between the members and thereby permit` the toggle to collapse.

9. A trip-free circuit breaker mechanism comprising a switch i member biased for movement to one position, an operating member mounted for movement on a floating center, and a connection between said members constructed and arranged to have its ell'ective length changed under lthe bias of said switch member. i

10. A trip-free circuit breaker mechanism comprising a switch member biased for n'iovement to one position, an operating mem# bei' for moving the switch member to another position mounted for movement on a `floating' center, and a link for connecting said members constructed and arranged for both rotatory and translatory movement relatively to one of the members whereby lthe effective length of the connection is variable under the bias of the switch member.

ll. A trip-free circuit breaker mechanism comprising a switch member biased for movement 'to one position, an operating member for moving the switch member to another position mounted for movement on a floating center, a link for connecting said members constructed and arranged for both rotatory and translatory movement relatively to one of the members whereby the effective length of the connection is variable under the bias of the switch member, and 4latching means Vfor preventing such relative movement whereby the operatingmember 'can be actuated in adirection to move the switch' member to the other position.

12. A trip-free circuit breaker mechanism comprising a switch member biased for movement to one position, anoperating member for moving the switch member to another position mounted for movement on a floating center, a linkl for connecting said members constructed and-arranged for both rotatory and translatory movement relativei ly to one of the members whereby the effective length of theconnection is variable un `der the bias of the switch member, latching means for preventing such relative movement whereby the operating member canl be actuated in a direction to move the switch member to the other position, and means forv the latching means whereby to perreleasing mit such relative movement.

13. A trip-free circuitbreaker mechanism comprising a switch arm biased for move'- ment tothe circuit open position, an operating lever for moving the arm to the circuit closed position against the bias thereof mounted on a floating pivot, a link connecting said arm and lever and arranged for both 4rotatory and translatory movement relatively to the lever under the bias of the ing lever in the opposite direction, the-mem-l arm, latching means for preventing such relative movement arranged to hold the link in an initial position whereby the lever can be actuated to move the arm tothe circuit closed position, means for effecting movement of the link from its initial position un- 4der the bias vof the arm arranged to release the latching means whereby to permit movement of the arm to the circuit open position, and means controlled by the arm and ai'- ranged during the opening movement thereof tov restore the link to its initial position.'

14. A trip-free circuitbreaker mechanism comprising a switch member biased for.

movement to one position, an operating member/for moving the switch member to another position mounted for movement on a floating center, a' connection between said members constructed and arranged for both rotatory and translatory movement relatively to one of the members under the bias ot'V the switch. member, latching means for preventing such relative movement arranged p to hold said connect-ion in an initial position ,whereby the operating member can be actu- 15. A pivoted .circuit controlling member biased for movement to the circuitV open po-v sition, an operating lever for moving the member to the circuit closed positionha link connecting the member and the lever, said link being constructed and arranged for rotatory and translatory movement on the -pivot of the lever and being subjected to :5v5A

Vthe bias of the member, latching means arranged on movement of the lever in one direction to engage the link in one position and to hold it and the lever against relative movement, said link and member forming a toggle whereby on movement of the operatber is moved to the circuit closed position, means for holding the member in the circuit closedposition While the latchingmeans is in latching position, and means for releasing 'the bias of the member, movemcntof the link to another position relatively to the lever suoli that the length of the toggle is changed.

16. 'A pivoted switch member biased for movement to one position, a pivoted operating member for moving the switch inember to another position, a link constructed and arranged for rotatpry and translatory movement on the pivot of one of the members, said link being connected to thecother member and subjectedto the bias vof the switch member, latching means arranged on movement ot the operating member in one direction to engage the link and vhold it in one positionrelatively to the one member, said link and thc` other of said members forming a toggle'whereby on movement of the operating member in the opposite direction the switch member is moved to the other position. means for holding. the switch -member in the other position while the latching means is inthe latching position, and means for releasing the latching means' whereby to effect the movement of the link to another position relatively to lthe one member such position rela-tively to the one member, said link and the other of said members forming a toggle whereby on movement of the operating member in the opposite direction the` switch member is moved to the other position, means for holding the switch member in the other position while the latching means is in the latching position, and means for releasing the latching means whereby to etl'e'ct the movementof the link to another` position relatively to the one' member'such that the length of the toggle is decreased and means for resetting the link in its first position during'the movement of the switch member to the other position.` Y

18. A pivoted`.circuit controlling` member biased for movement to the circuit open position, an operating lever for moving the member to the circuitclosed position, a link connecting the lmember and the lever, said link being constructed and arranged for rotatory and translatory movement on the pivot'of the lever and beingl subjected to the bias of thel member, latching means arranged on movement of the lever in one direction to engage the link in one position and to hold it and the lever against relative llO movement, said link and member forming a ment of the link to another position rela- 10 toggle whereby on movement of the opertively to the' lever such that the length of ating lever in the opposite direction, the the toggle is decreased, and means mountedl member is moved to the circuit closed posion the member and arranged to reset the link tion, means for holding the member in the in its first position during the movement of circuit closed position While the latching the member to the circuit open position. 15 means is in latching position, means for In Witness whereof, I have hereto set my releasing vthe latching means whereby to hand this 27th day of May, .1926.

effect, under the bias of the member` move- HARRIS D. DUN TON. 

